Preparation and surface-functionalization of dye-doped bioconjugated poly(styrene-co-maleimide) nanoparticles

[摘要] ENGLISH ABSTRACT: Standard methods used for detection of microbial contamination in water and food are basedon culturing of samples to increase the number of bacteria present to a detectable level.These tests are however time-consuming (requiring one to two days for results to begenerated) and labour intensive. The study described in this dissertation aims to developdye-doped poly(styrene-co-maleimide) nanoparticles conjugated to antibodies for the rapid(within a few hours) detection of E. coli in water via clustering of the nanoparticles aroundbacteria to create a concentrated and localised fluorescent signal.Pristine and dye-doped nanoparticles were synthesised according to a one-step (published)method, and surface-functionalised with formaldehyde and three different diaminecompounds. The percentage dye added to the particles was also varied in the study.The functionalised nanoparticles were characterised via FTIR, TEM, DSC, and Zetasizer.The emission properties of the dye-loaded NPs were measured with a spectrofluorometer.The functionalised nanoparticles were bioconjugated with avidin and antibodies. The extentof avidin attachment was quantified via the use of a biotin(5-fluorescein) conjugate and viaan avidin titration assay. The functionality of the bioconjugated nanoparticles was tested viaa sandwich assay and a centrifuge based assay with E. coli cultures. Fluorescencemicroscopy was also utilised to demonstrate the utility of the particles in creating localisedfluorescent signals indicating the presence of E. coli cells.

[发布机构] Stellenbosch University